Multi-color printed and embossed lid for cream jars and method for producing such lids

ABSTRACT

A method for producing a printed and embossed deep-drawn lid of aluminum that is circular in plan view. The method comprises: (a) printing an aluminum plate with at least one of a varnish and a paint; (b) cutting the aluminum plate; (c) deep drawing; (d) embossing; and (e) optionally, edge rolling. Steps (b), (c), (d) and optionally (e) are carried out with a single tool. A lid obtainable by this method is also disclosed.

Jars as packaging are sufficiently well known. They can be made fromdifferent materials, such as sheet metal, wood, plastic. Sheet-metaljars can be produced from different metals, for example, from aluminum,steel, brass. The jar can be produced from the metal by means oftrimming to size, folding, flanging or soldering or welding. Anothermethod is cold working, in particular deep drawing. The joining of sheetmetal edges is dispensed with thereby.

A jar can be closed by a lid. Lids are conceivable in many differentdesigns: there are hinged lids (box of cigars), screw lids (oil jar),push-on lids (tea jar, cookie jar or Nivea jar). The lid can also befirmly attached to the jar, as in the case of a canning jar.

The jar and/or lid are often designed for advertising purposes. To thisend the wall material can be coated with varnish and paint, polished,labeled and/or embossed, depending on the manufacturer's requirements.An interior coating with varnish and paint, metal or plastic can also beprovided.

Jars can have many conceivable shapes: in plan view they can berectangular, oval, round, octagonal, star-shaped or irregularly shaped(e.g., “Garfield” the cat, “Mickey Mouse”).

Most jars for practical use have a right angle between the jar base andwall, which keeps the space requirement low for shipping a plurality ofjars in a case. However, the lid is often not flat on the top, but moreor less curved.

The subject matter of this invention are jars, the lids of which aredesigned in a multi-colored manner and embossed, in particular varnishedand printed lids with lettering, which is designed in a multi-coloredmanner as well as emphasized by embossing. In particular the inventionrelates to lids that are deep-drawn from aluminum, round, curved and canbe produced in mass production.

The production of painted and deep-drawn aluminum lids is known per se.Production methods with high throughputs use a combined cutting,drawing, rolling tool.

A tool of this type is driven via a crankshaft and permits theproduction of 200 lids per minute on average. For each stroke, one lidis punched out of a sheet-metal plate and subsequently deep-drawn. Theremaining edges on the lid edge are rolled so that the finished lid canbe blown out.

A suitable tool is shown in FIG. 1. The movements of the tool during acycle are likewise shown. The figure thereby shows the principle of aconventional cycle as well as of a cycle according to the invention.

The tool comprises a bottom die (1), (2), (3) and an upper die (4) and(5). The bottom die has a core (1), a die ring (3) and a so-called blankholder (2). The blank holder (2) has a rolling ring (2 a) on the topfacing towards the core (1).

The upper die comprises a male die (4) and an ejector (5), around whichthe male die (4) is oriented. A combination of this type of upper dieand bottom die is shown in FIG. 1. The upper die is driven by acrankshaft. At the upper dead-center position) (0°) the tool is at itshighest position during a cycle.

After the sheet-metal plate has been guided over the bottom die, thecycle begins (FIG. 1A): The upper die is lowered onto the bottom die andgrips the sheet-metal plate with the male die (4) and presses it ontothe blank holder (2). This occurs with a crankshaft position ofapproximately 135° ( 6/8 stroke).

When the movement of the crankshaft continues further (FIG. 1B), theblank holder (2) is slowly lowered, whereby the die ring (3) cuts acircular blank out of the sheet-metal plate (likewise 135°).

In the further course of the cycle up to the lower dead-center position(FIG. 1C), the male die (4) and blank holder (2) gradually advancedownwards, whereby the lid is slowly formed from the circular blank overthe core (1). Material thereby slides through slowly between the blankholder (2) and the male die (4), whereby the side wall of the lid isformed. After approximately ⅞ of the stroke, the ejector (5) is placedon the core (1) in a spring-loaded manner. Now the top of the lid isformed between the core (1) and the ejector.

During the last ⅛ of the stroke (FIG. 1D), the ejector (5) isstationary, the male die (4) continues moving. At the lower dead-centerposition (180°), a hat-shaped structure is formed. The hat brim therebyremains between the core (1) and male die.

In the upward movement again after passing through the lower dead-centerposition of the crankshaft (FIG. 1E), first the blank holder (2) isconveyed upwards, whereupon the male die (4) slowly yields backwards,but the ejector (5) remains stationary for ⅛ of the stroke. Theremaining hat brim is thus pressed into the rolling ring of the blankholder and shaped to form a roller-shaped edge of the lid. This allhappens between a crankshaft position from 180 through about 200°.

Subsequently, the upper die is removed from the bottom die again (FIG.1F) and takes the lid with finished shape with it (FIG. 1G). This lid isblown out from the tool through an ejector stroke and an air flow (FIG.1H) at a crankshaft position between 330 and 360°.

A modern machine permits about 200 strokes per minute, thus about 12,000lids per hour can be shaped with one tool. Generally, 3 to 5 tools areused simultaneously, whereby 36,000-60,000 lids can be produced perhour.

With such high throughputs, the sheet-metal plate must be guided veryexactly under the tools located at the upper dead-center position.Furthermore, it must be ensured that the spacing between the male die(4) in the upper ring and die ring (3) in the bottom die peripherally isabout 3 1/100 mm=30 μm. It must likewise be ensured that the drawinggap, that is, the space between the core (1) and the blank holder (2),is exactly the sheet metal thickness. This is not a trivial function inthe case of the very heavy tools exposed to high dynamic stresses.Conventional upper dies are therefore generally arranged in a rotatablemanner, because this considerably facilitates the alignment of the upperdie to the bottom die for adjusting a correct drawing gap.

In addition to the male die (4), the ejector (5) is a highly loaded toolpart. This tool part has different bores that render possible theattachment, dismantling and ventilation of the tool. In a conventionalmanner, the bores and ventilation holes are distributed in the ejector(5) over virtually the entire area of the ejector (5). As a rule, 8-12bores are provided.

However, no bores can be provided on the outer annular area of theejector oriented towards the male die (4). This area represents afurther clamping area of the tool, which is necessary for absorbing thecompressive forces during the rolling process between the core (1) andthe ejector (5).

If an additional embossing of the lid is also provided, the lid must beseparately embossed once again in a subsequent process step afterejection from the cutting/drawing/rolling tool. It is relatively easy,if the embossing does not have to be carried out in an aligned manner,e.g., if an embossing of any orientation is simply to be carried out ona single-color lid.

However, it becomes very complex when the embossing may have only asingle position of the lid on the embossing tool, if, e.g., a letteringis to be emphasized by the embossing as well as by the imprinting, suchas, e.g., in the case of a blue jar lid with “Nivea” in white lettering,where the lettering in addition is to be embossed over the entire area.

The alignment is hardly possible mechanically and would have to be doneby hand. This may be the reason why lids of this type that are embossedand imprinted hitherto have not been available on the market at all.

An integration of the embossing step into the described automatedcutting, drawing rolling process is not easily accomplished either:

On the one hand, the free rotatability of the upper die, which isnecessary for the alignment of the upper die to the bottom die, does notallow a lettering to project, since the rotation can result in positionsin which the positive embossed shape does not coincide with the negativeembossed shape on the upper die or bottom die. This leads to damage tothe embossing dies during a throughput cycle.

On the other hand, there is no room at all for lettering on the ejector(5) of the upper die due to the numerous bores, which are used forventilation and attachment purposes.

Furthermore, the embossing pressure and embossing time must besufficient to be able to emboss the very elastic aluminum at all. Thealuminum—Mg-containing Al alloys are used, which are considerably moreelastic than pure Al—tends to spring back to the initial shape in thecase of an embossing force action of only short duration, whereby thefreshly embossed edges easily become round or flat. This is no problemat all with sheet steels, because steel is much more easily malleable.

Furthermore, with the in-process embossing of an aluminum lid, theso-called frog effect occurs: through material tension, during movementthe lid tends to make a noise that is reminiscent of a snap-action toyand makes a very audible “plop” sound. However, this is extremelyundesirable.

Furthermore, the tool must be designed such that unembossed lids canalso be produced easily. A tool that can be used exclusively forembossed lids represents an excessively high expense for a process ofthis type.

The tool must therefore be provided such that it can be converted to astandard tool without an embossing punch by just a few actions.

This bundle of objectives is attained through a method for producingprinted and embossed deep-drawn aluminum lids that are circular in planview, characterized by a sequence of the following process steps:

-   -   a) coating, in particular printing, an aluminum plate with        varnish and/or paint,    -   b) cutting the aluminum plate,    -   c) deep drawing,    -   d) embossing,    -   e) optionally edge rolling, wherein the steps (b), (c), (d) and        optionally (e) are carried out with a single tool. The invention        also comprises a varnished, printed and embossed deep-drawn        aluminum lid that is circular in plan view, substantially in the        shape of a cylinder open on one side, in which the printing on        the substantially flat surface has at least one contour that        also represents the contour of the embossing, obtainable through        a sequence of the steps referenced in the previous sentence.

Through the method according to the invention it is possible tointegrate the embossing operation into the cutting/drawing/rollingoperation in a single-step process. The embossing force is sufficient toemboss clean edges. It is easily possible to align the embossing withthe pre-painted lettering, because the sheet-metal plate is guidedthrough under the embossing die only once by a two-axle servo system.Through the special design of the ejector, it is possible to producethese jar lids free from the frog effect. Furthermore, the embossingdies recessed in the tools can be easily replaced by non-contoured dies.It is thus possible to produce unembossed lids on the same tool.

It is preferred if in all this the dimensional variation between thecontour of the painting and the contour of the embossing is no more than0.3 mm. It is preferred if the tool comprises an upper die and a bottomdie, which are driven by a crankshaft and the bottom die has at leastone core (1), a blank holder (2) with integrated rolling ring (2 a) anda die ring (3), the upper die has a male die (4) and an ejector (5) andthe ejector has an embossing tool in the area of its center, ventilationand mounting bores outside the embossing die and an annular clampingarea (6) near to the edge, the edges of which have a spacing of at least8 mm and which is free from bore holes and mounting holes, wherein theupper die is not freely rotatable and on the bottom die likewise has anembossing die, wherein the embossing dies are aligned to one another andare recessed in the ejector and core (1).

It is further preferred thereby if the process steps take place asfollows: (b) cutting the aluminum plate 135 to 145° after upperdead-center position, (c) deep drawing 140 to 170° after upperdead-center position, (d) embossing 170 to 180° after upper dead-centerposition, (e) optionally edge rolling 180 to 200° after upperdead-center position and (f) optionally blowing out 330 to 360° afterupper dead-center position, in each case based on the position of thedriving crankshaft. Furthermore, it is preferred if the embossing die isprovided on the core (1) with two mounting bores and twoventilation/ejector bores. It is very particularly preferred if the toolhas gap widths between the bottom die and the upper die and between themale die (4) and the blank holder (2) and core (1) of 20 to 40 μm.Furthermore, it is particularly preferred if the tool has an ejectorwhich is arranged with respect to the later lid shape towards the openside of the lid at least with 50% of its area by 0.4 to 0.9 mm. It isparticularly advantageous if the production is carried out on a toolwith throughputs of at least 150, particularly preferably at least 190pieces/min. It is thereby very advantageous if the lid is made of anAlMg alloy with 2.5% Mg. The invention also comprises a jar containing acosmetic preparation, in which the lid was produced as described above.

1.-11. (canceled)
 12. A method for producing a printed and embosseddeep-drawn lid of aluminum that is circular in plan view, wherein themethod comprises: (a) printing an aluminum plate with at least one of avarnish and a paint; (b) cutting the aluminum plate; (c) deep drawing;(d) embossing; and (e) optionally, edge rolling, (b), (c), (d) andoptionally (e) being carried out with a single tool.
 13. The method ofclaim 12, wherein the method comprises, based on a position of a drivingcrankshaft: (b) cutting the aluminum plate 135° to 145° after an upperdead-center position; (c) deep drawing 140° to 170° after the upperdead-center position; (d) embossing 170° to 180° after the upperdead-center position; (e) optionally, edge rolling 180° to 200° afterthe upper dead-center position; and (f) optionally, blowing out 330° to360° after the upper dead-center position.
 14. The method of claim 12,wherein a dimensional variation between a contour of an imprint and acontour of an embossing is no more than 0.3 mm.
 15. The method of claim12, wherein the tool has an ejector which is arranged with respect to aprospective lid shape towards an open side of the lid at least with 50%of its area by from 0.4 mm to 0.9 mm.
 16. The method of claim 12,wherein (i) the tool comprises an upper die and a bottom die driven by acrankshaft, (ii) the bottom die comprises at least a core, a blankholder comprising an integrated rolling ring, and a die ring, (iii) theupper die comprises a male die and an ejector, (iv) the ejector has anembossing die in its central area, ventilation and mounting boresoutside the embossing die and an annular clamping area near an edgethereof, edges of which have a spacing of at least 8 mm and which isfree from bore holes and mounting holes, (iv) the upper die is notfreely rotatable, (v) the bottom die also comprises an embossing die,and (vi) the embossing dies of the upper and lower dies are aligned andare recessed in the ejector and the core.
 17. The method of claim 16,wherein the embossing die comprises on the core two mounting bores andtwo ventilation/ejector bores.
 18. The method of claim 16, wherein thetool has gap widths between the bottom die and the upper die and betweenthe male die and the blank holder and core of from 20 μm to 40 μm. 19.The method of claim 12, wherein the tool has a throughput of at least150 pieces/min.
 20. The method of claim 12, wherein the tool has athroughput of at least 190 pieces/min.
 21. The method of claim 12,wherein the aluminum plate comprises an AlMg alloy comprising 2.5% ofMg.
 22. A lid for a jar, wherein the lid comprises aluminum and ispainted, printed, deep-drawn and embossed, circular in plan view, andsubstantially has a shape of a cylinder which is open on one side, andwherein an imprint on a substantially flat surface has at least onecontour that substantially coincides with a contour of an embossing. 23.The lid of claim 22, wherein a dimensional variation between the contourof the imprint and the contour of the embossing is no more than 0.3 mm.24. The lid of claim 22, wherein the lid is obtainable by a method whichcomprises: (a) coating an aluminum plate with at least one of a varnishand a paint; (b) cutting the aluminum plate; (c) deep drawing; (d)embossing; (e) optionally, edge rolling, (b), (c), (d) and optionally(e) being carried out with a single tool.
 25. The lid of claim 24,wherein the method comprises, based on a position of a drivingcrankshaft: (b) cutting the aluminum plate 135° to 145° after an upperdead-center position; (c) deep drawing 140° to 170° after the upperdead-center position; (d) embossing 170° to 180° after the upperdead-center position; (e) optionally, edge rolling 180° to 200° afterthe upper dead-center position; and (f) optionally, blowing out 330° to360° after the upper dead-center position.
 26. A jar containing acosmetic preparation, wherein the jar comprises the lid of claim
 22. 27.A tool for making a lid for a jar which comprises aluminum and ispainted, printed, deep-drawn and embossed, circular in plan view, andsubstantially has a shape of a cylinder which is open on one side,wherein the tool comprises an upper die and a bottom die driven by acrankshaft, the bottom die comprises at least a core, a blank holdercomprising an integrated rolling ring, and a die ring, the upper diecomprises a male die and an ejector, the ejector has an embossing die inits central area, ventilation and mounting bores outside the embossingdie and an annular clamping area near an edge thereof, edges of whichhave a spacing of at least 8 mm and which is free from bore holes andmounting holes, the upper die is not freely rotatable, the bottom diealso comprises an embossing die, and the embossing dies of the upper andlower dies are aligned and are recessed in the ejector and the core. 28.The tool of claim 27, wherein the ejector is arranged with respect to aprospective lid shape towards an open side of the lid at least with 50%of its area by from 0.4 mm to 0.9 mm.
 29. The tool of claim 27, whereinthe embossing die comprises on the core two mounting bores and twoventilation/ejector bores.
 30. The tool of claim 27, wherein the toolhas gap widths between the bottom die and the upper die and between themale die and the blank holder and core of from 20 μm to 40 μm.
 31. Thetool of claim 27, wherein the tool has a throughput of at least 150pieces/min.